PROJECT SUMMARY/ABSTRACT To address obesity and type 2 diabetes prevention across all University of California (UC) campuses, a new UC-wide Diabetes Prevention Initiative (referred to as the UC DPP Initiative) was launched in 2018. In an innovative scientific partnership between researchers and the university, the UC Office of the President will provide access to electronic health record (EHR) and insurance claims for UC beneficiaries, as well as campus-level data across five UC campuses to conduct a rigorous evaluation. We will use a well-established reach, effectiveness, adoption, implementation, and maintenance (RE-AIM) evaluation framework to ensure a comprehensive evaluation. To assess the effectiveness of the UC DPP Initiative, we will examine mean percent weight change at 12-months (primary outcome) and 24-months within and between overweight/obese UC beneficiaries at risk for type 2 diabetes. To assess reach, we will report the proportion of eligible UC beneficiaries who engage in DPP (attend >9 and >16 sessions) and their representativeness of UC beneficiaries overall. To examine adoption, implementation and maintenance, we will conduct site visits and qualitative interviews, focused on assessing the degree of implementation, identifying barriers and facilitators associated with implementation, and unanticipated consequences. In summary, this is a unique opportunity to conduct an imperative evaluation using diverse data sources across the UC system. Findings from this study will inform future UC-wide programs targeting obesity and type 2 diabetes prevention, as well as dissemination of effective strategies to other large university systems and employers.